c/6 orthogonal is an orthogonal speed that is equivalent to one sixth of the speed of light.
The first c/6 orthogonal spaceship to be found was the dragon, discovered in April 2000 by Paul Tooke using David Eppstein's spaceship search program, gfind. Two dragons can pull a toad in a manner similar to a toad sucker, and this was the only known way to create c/6 orthogonal spaceships until March 2006 when Paul Tooke discovered 274P6H1V0. In October 2008 Paul Tooke found 114P6H1V0, based on a pushalong component discovered by Hartmut Holzwart. This component provides a forward domino spark that can be used to support the component itself, resulting in an extensible spaceship. In May 2009 Hartmut Holzwart found another pushalong component for this spaceship, as well as a much smaller c/6 orthogonal spaceship, 56P6H1V0. Many c/6 spaceships have since been found by Tim Coe, Josh Ball, Matthias Merzenich, Dongook Lee, and Tanner Jacobi.
- Dave Greene (March 8, 2009). "New c/6 Extensible Spaceship".
- Heinrich Koenig (May 31, 2009). "New c/6 Spaceships".
- Matthias Merzenich (July 27, 2017). Re: Spaceship Discussion Thread (discussion thread) at the ConwayLife.com forums
- Goldtiger997 (March 22, 2020). Re: Small Spaceship Syntheses (discussion thread) at the ConwayLife.com forums
- Martin Grant (March 25, 2020). Re: Small Spaceship Syntheses (discussion thread) at the ConwayLife.com forums
- Nico Brown (July 26, 2017). Re: Spaceship Discussion Thread (discussion thread) at the ConwayLife.com forums